In a short statement today, Ofcom notes that Channel 4 has informed the regulator that it will no longer be operating the "second commercial DABmultiplex" or providing the radio stations.
This in effect cancels the Channel 4 Radio, E4 Radio and Pure4 radio stations.
The ofcom statement reads:
Channel 4 has today informed Ofcom of its decision to withdraw from 4 Digital Group, the consortium which was awarded a licence for the second national commercial DAB radio multiplex last year.
Ofcom recognises that the economic environment is very challenging and that all organisations need to make decisions in light of the circumstances they face.
Ofcom and the Government have supported DAB through the licensing of services and Ofcom continues to believe that DAB offers listeners real benefits. There are now 7.7 million DAB devices in the UK with 11 per cent of all radio listening through these.
Ofcom will meet the other members of 4 Digital Group over the next few days to discuss how they propose to take matters forward. Ofcom is also in discussions with other multiplex operators and the BBC, to consider how best to secure a viable outcome which is in the interests of radio listeners and the industry.
In addition, Ofcom continues to support the work of the Digital Radio Working Group which is considering the obstacles to the further take-up of digital radio.
The BBC's Tim Davie, the Director of Audio & Music, said:
"Today's announcement by Channel 4 is disappointing news for UK radio as plurality of services is very much in the interest of all listeners. However, we appreciate that, in light of the current economic climate, Channel 4 felt that they had to leave the 4DG consortium.
"While we regret this, we remain positive about the future of digital radio and DAB. Going forward, the BBC is committed to work with the Digital Radio Working Group and all other parties to lead the growth of digital radio.
"DAB will continue to offer high quality services that are proven to have significant appeal to radio listeners, and we look forward to working in partnership with all the industry to drive further growth of the platform."